I will go to the grave swearing that Jan 2011 would not have been so epic if la nina were weaker....strong east based la nina and modoki el nino events are rare birds, and it's why seasons like 2010-2011, 1955-1956, 2002-2003 and 2009-10 are so exceptional. It's about the location of the forcing, and if it is well placed, then you want it to be a very prominent hemispheric driver.